Using Modifier 59 (Distinct Procedural Service) Effectively

A modifier should never be used just to get higher reimbursement or to get paid for a procedure that will otherwise be bundled with another code. Modifier 59 describes a distinct procedural service and is used to identify procedures and services that are not normally reported together. For example, it should be used when coding for a different session, different procedure or surgery, different site or organ system, separate incision/excision, separate lesion (non-contiguous lesions in different anatomic regions of the same organ), or a separate injury. Modifier 59 should not be used on Evaluation and Management Codes, and should only be used when no other modifier is accurate.

Difficulties in using modifier 59:

  • The 59 modifier is one of the most misused modifiers. The most common reason it should be used is to indicate that two or more procedures were performed at the same visit but to different sites on the body.
  • Unfortunately, many times it is used to prevent a service from being bundled or added in with another service on the same claim. It should never be used strictly to prevent a service from being bundled or to bypass the insurance carrier’s edit system.
  • 59 should also only be used if there is no other, more appropriate modifier to describe the relationship between two procedure codes. If there is another modifier that more accurately describes the services being billed, it should be used instead of the 59 modifier.
  • When using the 59 modifier to indicate a distinct and separate service, documentation should be in the patient’s medical file that substantiates that the services were performed separately. The insurance carrier may request to review the record to deem if the modifier is being appropriately used before reimbursing the full amount for the modified CPT code.
  • It’s important to note that the use of the 59 modifier does not require that there be a different or separate diagnosis code for each of the services billed. As such, simply using different diagnosis codes for each of the services performed does not support the use of the modifier.


As mentioned above, Modifier 59 may be used appropriately for procedures performed on different anatomic sites during the same encounter when the procedures are performed on different organs or on different, noncontiguous lesions in the same organ.

  1. If the patient were having a nerve conduction study with CPT codes 95900 and 95903 being billed. If the two procedures are done on separate nerves, then the modifier 59 should be used to indicate that. If the codes were performed on the same nerve, then should not be used. The biller should never be the one to add the modifier 59 to a claim, even if she knows that billing the services without the modifier will result in bundling or a denial. The modifier 59 should only be added by the provider or by a coder who has access to the patient’s chart.
  2. Proper use of Modifier 59 may be when a surgeon performs a laparoscopic partial nephrectomy (CPT 52343) on two separate, noncontiguous lesions in the same kidney. In contrast, CPT 50542 is defined as laparoscopic ablation of a renal mass lesion(s); therefore the use of a 59 or XS modifier is not appropriate when ablating more than one lesion. As intraoperative guidance and monitoring when performed is part of the description of CPT 50542, it should not be separately reported or billed. However, if ultrasound guidance is used to biopsy a separate lesion, consider using CPT 76942, ‘Ultrasonic guidance for needle placement (e.g., biopsy, aspiration, injection, and localization device), imaging supervision and interpretation’ with Modifier 59, or the XP modifier if unrelated to the laparoscopic kidney tumor ablation.
  3. The kidney and the ureter are separate structures, so Modifier 59 (or the XS modifier) may be appropriately used when ureteroscopy and laser lithotripsy are performed on separate, noncontiguous stones in the ureter and kidney on the same side at the same session. Some argue that stones are lesions and therefore multiple, noncontiguous stones in the ureter, or multiple noncontiguous stones in the kidney, may fit the definition of proper use of 59 or XS, whereas others argue that they are no lesions. In these cases, local payer rules should be followed.
  4. Instillation of an antineoplastic agent (CPT 51740) such as mitomycin is bundled to most cystoscopic procedures, including bladder tumor treatments. If the antineoplastic agent is instilled intra-operatively, two codes should not be billed. However, if both procedures are performed on the same date but at different encounters, they should be separately billable. If a patient undergoes a transurethral resection of a medium-sized bladder tumor (CPT 52235) in an ambulatory setting, is discharged, then goes to the office for the instillation of the antineoplastic agent, it is appropriate to bill CPT 51740 with an XE modifier.

If you are the biller and you believe that the modifier 59 would be appropriate but was not indicated, you should go back to the provider to see if it was omitted by mistake. Don’t just add the modifier to the claim without substantial evidence that it is needed. However, it is important to check with your own local carrier for their rules with regard to which modifiers they accept and under which circumstances. Misusing 59, or any other modifier can cause a payer to deny your claim altogether. Avoid claim issues by making sure to always use it properly. As always, bills should only be submitted for legitimately billable services.


How Best to Use 59 Modifier


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